Composite fastness is an important index of composite membrane, which closely affects the usage of membrane. In this study, we will do a comparative analysis of the effect of printing inks with different colors on the sample composite fastness, through testing the peel strength of samples. Meanwhile, it can provide a reference for manufacturers to analysis the composite fastness of their product by introducing test principle, test equipment LTS-05 tensile tester and its parameters, applications, test procedures, etc.
Keywords: Composite fastness, peel strength, printing inks, plastic composite films, Tensile testing machine, composite membrane
Composite membranes are composited from two or more constituent single-layer films by adhesives, with the aim of making a full use of each single-layer film and meet the packaging requirement of products. Take plastic-aluminum films PET/Al/PE for instance, three single-layers have different function in the composite from each other, PET is printing layer, Al performs as a permeability layer and PE film is the sealing layer. PET and PE film can protect Al from winkling and pinholes. If the composite fastness is poor, the membrane will easy to layer and Al can’t be protected properly. Compression or flexing will easy damage the aluminum layer, which will affect the permeability property of composite membrane. Moreover, poor composite fastness will also affect the composites’ impact and puncture resistance property. Therefore, a proper composite fastness is a prerequisite for composite membrane to reach the expected performance.
There are many factors affecting the composite fastness of membranes, such as the styles of adhesives, ratios of each component, quantity of adhesives, process of compositing, inks and etc. In this study, we will comparatively analyze the effect of printing inks with different colors on the composite fastness.
Composite Membrane Pic.1
Composite fastness is usually characterized by Peel Strength. In this study, we will conduct peel strength test on the samples according to GB 8808-1988 <test method of Peel Strength Testing of flexible composite materials>
2. Test Specimens
The Specimens in this study are two-layer composite films with three different ink colors on the surface.
3、Test Equipment
The Equipment used is LTS-05 Auto Tensile Tester, which is R&D and manufactured by Link Testing Instruments Co., Ltd.
LTS-05 Auto Tensile Tester
4.Test Principle
This study will analyze the effect of different ink on composite fastness through the comparison of peel strength of samples with different ink colors on the surface. Peel strength is the force to separate the layers of samples in one unit. Mounted the two sides of sample to the two grips, and move the upper grip in relative direction during test. The changes of force and displacement are separately recorded by the load cell fixed on the driven grip and embedded displacement transducer. The peel strength then displays directly.
5.Test Parameters.
The equipment has two optional loads of 500N and 50N . Test accuracy is better than 0.5% FS, which guarantees the test accuracy of test results. Have stretching and compressing test modes with test speeds 50 mm/min、100 mm/min、150 mm/min、200 mm/min、250 mm/min、300 mm/min、500 mm/min; Pneumatic clamping system provides the even clamping force for specimen; 950mm test stroke; over-travel protection, overload protect, and automatic position reset for safe test operation; equipped with more than 100 grips for tests of more than 1000 materials; Customization available according to differential test materials.
6.Test Applications.
1) LTS-05 Auto Tensile Tester is applicable to tensile, peeling, deformation, tearing, heat sealing, adhesive, puncture force, opening force and low speed unwrapping force as well as other performance of plastic films, composite materials, soft package materials, plastic flexible tube, adhesives, adhesive tape, label stickers, medical plasters, release paper, protection films, combined caps, aluminum foil, diaphragm, back sheets, non-woven fabrics, rubber, paper, etc.
2)Referring Test Standards includes ISO 37, ASTM E4, ASTM D882, ASTM D1938, ASTM D3330, ASTM F88, ASTM F904, JIS P8113, GB8808, etc more than 30 domestic and international standards
7、Test Procedures
1) Specimens preparation: Cut specimens from the sample material along a same direction. 5 pieces of specimens for each color with width 15.0mm and length 10cm at least
2） Precondition: Put the specimen under 23±2℃、RH45% ~ 55% for 4hours
3）pre-peeling: Peel the specimen from one end by 3cm
4) Parameters Setting: Set the test speeds 300mm/min. specimen width, specimen number in the software of the equipment.
5) Sample Mounting: Clamp the two ends of the peeled part of the specimen with the upper and lower sample grips. Make sure the longitudinal axis of the specimen coincides with the line of centers of the uppwer and lower sample grips.
6) Test Over: Record the peel strength value displayed on the equipment when test over. Repeat the procedures on the other 4 samples.
8. Test Results
The peel strength in the study is the average value of these 5 samples for each color sample. Peel Strength of non printed sample is 1.036N/15mm, 0.877N/15mm for White printed sample and 0.571 N/15mm for yellow printed sample.
9. Conclusion
Printing process, ink quality, compatibility of adhesives and inks and other factors will impact the composite fastness of the composite membranes. In this study, we test the peel strength of plastic composite films with different printed colors. Test procedure is simple, equipment used is intelligent and test results are displayed directly. The results showed that the unprinted composite has the best fastness and yellow printed sample has the poorest fastness among the three specimens. This may be caused by the different compatibility of adhesives and inks.
Link Testing Instrument Co., Ltd is a high-tech company which is focus on the R&D and manufacturing packaging test equipment and providing test services. We are dedicated to providing integrated professional test instruments and services for packaging research and quality control. Visit our website www.linktesting.org for more details.
